Code question - subpanel for second floor

Hi again,

So I'm looking at my second floor remodel plans, and I'm thinking it will actually end up being a lot easier if I just wire my second floor with a 60A subpanel rather than running individual wires for all the circuits up from the basement.

I'd run a 6/3 cable from the basement main panel up to a subpanel on the second floor, and then branch all the second floor's circuits (bedroom, hall, bathroom) off of there. The only "separate" circuit wire that would be coming up is for the smoke detectors, which obviously have to be tied in to all the other ones around the house.

My question is, are there any code requirements with respect to how this is done?

Specifically:

1. The subpanel will easily fit into the wall framing, between two studs. Can I just put it there then drywall around it as long as it obviously is still fully accessible?

2. Any location requirements? I have a little "alcove" at the end of my hall which used to be a small walk-in closet but I am going to de-frame it and just have it be part of the hall - it'd also be a perfect place for the subpanel based on how the wire run will be coming up from the basement and also wiring runs to the rest of the floor. OK?

3. Is it allowed to build out a little wooden cover over the spot where the panel is, just for aesthetic's sake? Was thinking I could build a lightweight wooden door in a little frame and mount it over the panel, thus leaving easy access to get inside and work the breakers or even open the panel, but can be closed to make the area look nice.

Thanks for the advice. I'm going to run the 6/3 straight up from the basement directly upwards to where the panel will be. This makes the cable run the easiest. It will end up being in a sort of "open" area - on the wall in the hall - but if I cover it with a wood "door" like I said it'll end up looking attractive and still be accessible when needed.